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Green_GoodERP18_FSJ_Standard/PostgreSQL/doc/postgresql/html/sql-createtable.html

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  1. <?xml version="1.0" encoding="UTF-8" standalone="no"?>

  2. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>CREATE TABLE</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets V1.79.1" /><link rel="prev" href="sql-createsubscription.html" title="CREATE SUBSCRIPTION" /><link rel="next" href="sql-createtableas.html" title="CREATE TABLE AS" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">CREATE TABLE</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="sql-createsubscription.html" title="CREATE SUBSCRIPTION">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><th width="60%" align="center">SQL Commands</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 12.4 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="sql-createtableas.html" title="CREATE TABLE AS">Next</a></td></tr></table><hr></hr></div><div class="refentry" id="SQL-CREATETABLE"><div class="titlepage"></div><a id="id-1.9.3.85.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">CREATE TABLE</span></h2><p>CREATE TABLE — define a new table</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis">

  3. CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] <em class="replaceable"><code>table_name</code></em> ( [

  4.   { <em class="replaceable"><code>column_name</code></em> <em class="replaceable"><code>data_type</code></em> [ COLLATE <em class="replaceable"><code>collation</code></em> ] [ <em class="replaceable"><code>column_constraint</code></em> [ ... ] ]

  5.     | <em class="replaceable"><code>table_constraint</code></em>

  6.     | LIKE <em class="replaceable"><code>source_table</code></em> [ <em class="replaceable"><code>like_option</code></em> ... ] }

  7.     [, ... ]

  8. ] )

  9. [ INHERITS ( <em class="replaceable"><code>parent_table</code></em> [, ... ] ) ]

  10. [ PARTITION BY { RANGE | LIST | HASH } ( { <em class="replaceable"><code>column_name</code></em> | ( <em class="replaceable"><code>expression</code></em> ) } [ COLLATE <em class="replaceable"><code>collation</code></em> ] [ <em class="replaceable"><code>opclass</code></em> ] [, ... ] ) ]

  11. [ USING <em class="replaceable"><code>method</code></em> ]

  12. [ WITH ( <em class="replaceable"><code>storage_parameter</code></em> [= <em class="replaceable"><code>value</code></em>] [, ... ] ) | WITHOUT OIDS ]

  13. [ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]

  14. [ TABLESPACE <em class="replaceable"><code>tablespace_name</code></em> ]

  15. 

  16. CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] <em class="replaceable"><code>table_name</code></em>

  17.     OF <em class="replaceable"><code>type_name</code></em> [ (

  18.   { <em class="replaceable"><code>column_name</code></em> [ WITH OPTIONS ] [ <em class="replaceable"><code>column_constraint</code></em> [ ... ] ]

  19.     | <em class="replaceable"><code>table_constraint</code></em> }

  20.     [, ... ]

  21. ) ]

  22. [ PARTITION BY { RANGE | LIST | HASH } ( { <em class="replaceable"><code>column_name</code></em> | ( <em class="replaceable"><code>expression</code></em> ) } [ COLLATE <em class="replaceable"><code>collation</code></em> ] [ <em class="replaceable"><code>opclass</code></em> ] [, ... ] ) ]

  23. [ USING <em class="replaceable"><code>method</code></em> ]

  24. [ WITH ( <em class="replaceable"><code>storage_parameter</code></em> [= <em class="replaceable"><code>value</code></em>] [, ... ] ) | WITHOUT OIDS ]

  25. [ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]

  26. [ TABLESPACE <em class="replaceable"><code>tablespace_name</code></em> ]

  27. 

  28. CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] <em class="replaceable"><code>table_name</code></em>

  29.     PARTITION OF <em class="replaceable"><code>parent_table</code></em> [ (

  30.   { <em class="replaceable"><code>column_name</code></em> [ WITH OPTIONS ] [ <em class="replaceable"><code>column_constraint</code></em> [ ... ] ]

  31.     | <em class="replaceable"><code>table_constraint</code></em> }

  32.     [, ... ]

  33. ) ] { FOR VALUES <em class="replaceable"><code>partition_bound_spec</code></em> | DEFAULT }

  34. [ PARTITION BY { RANGE | LIST | HASH } ( { <em class="replaceable"><code>column_name</code></em> | ( <em class="replaceable"><code>expression</code></em> ) } [ COLLATE <em class="replaceable"><code>collation</code></em> ] [ <em class="replaceable"><code>opclass</code></em> ] [, ... ] ) ]

  35. [ USING <em class="replaceable"><code>method</code></em> ]

  36. [ WITH ( <em class="replaceable"><code>storage_parameter</code></em> [= <em class="replaceable"><code>value</code></em>] [, ... ] ) | WITHOUT OIDS ]

  37. [ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]

  38. [ TABLESPACE <em class="replaceable"><code>tablespace_name</code></em> ]

  39. 

  40. <span class="phrase">where <em class="replaceable"><code>column_constraint</code></em> is:</span>

  41. 

  42. [ CONSTRAINT <em class="replaceable"><code>constraint_name</code></em> ]

  43. { NOT NULL |

  44.   NULL |

  45.   CHECK ( <em class="replaceable"><code>expression</code></em> ) [ NO INHERIT ] |

  46.   DEFAULT <em class="replaceable"><code>default_expr</code></em> |

  47.   GENERATED ALWAYS AS ( <em class="replaceable"><code>generation_expr</code></em> ) STORED |

  48.   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <em class="replaceable"><code>sequence_options</code></em> ) ] |

  49.   UNIQUE <em class="replaceable"><code>index_parameters</code></em> |

  50.   PRIMARY KEY <em class="replaceable"><code>index_parameters</code></em> |

  51.   REFERENCES <em class="replaceable"><code>reftable</code></em> [ ( <em class="replaceable"><code>refcolumn</code></em> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]

  52.     [ ON DELETE <em class="replaceable"><code>referential_action</code></em> ] [ ON UPDATE <em class="replaceable"><code>referential_action</code></em> ] }

  53. [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]

  54. 

  55. <span class="phrase">and <em class="replaceable"><code>table_constraint</code></em> is:</span>

  56. 

  57. [ CONSTRAINT <em class="replaceable"><code>constraint_name</code></em> ]

  58. { CHECK ( <em class="replaceable"><code>expression</code></em> ) [ NO INHERIT ] |

  59.   UNIQUE ( <em class="replaceable"><code>column_name</code></em> [, ... ] ) <em class="replaceable"><code>index_parameters</code></em> |

  60.   PRIMARY KEY ( <em class="replaceable"><code>column_name</code></em> [, ... ] ) <em class="replaceable"><code>index_parameters</code></em> |

  61.   EXCLUDE [ USING <em class="replaceable"><code>index_method</code></em> ] ( <em class="replaceable"><code>exclude_element</code></em> WITH <em class="replaceable"><code>operator</code></em> [, ... ] ) <em class="replaceable"><code>index_parameters</code></em> [ WHERE ( <em class="replaceable"><code>predicate</code></em> ) ] |

  62.   FOREIGN KEY ( <em class="replaceable"><code>column_name</code></em> [, ... ] ) REFERENCES <em class="replaceable"><code>reftable</code></em> [ ( <em class="replaceable"><code>refcolumn</code></em> [, ... ] ) ]

  63.     [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] [ ON DELETE <em class="replaceable"><code>referential_action</code></em> ] [ ON UPDATE <em class="replaceable"><code>referential_action</code></em> ] }

  64. [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]

  65. 

  66. <span class="phrase">and <em class="replaceable"><code>like_option</code></em> is:</span>

  67. 

  68. { INCLUDING | EXCLUDING } { COMMENTS | CONSTRAINTS | DEFAULTS | GENERATED | IDENTITY | INDEXES | STATISTICS | STORAGE | ALL }

  69. 

  70. <span class="phrase">and <em class="replaceable"><code>partition_bound_spec</code></em> is:</span>

  71. 

  72. IN ( <em class="replaceable"><code>partition_bound_expr</code></em> [, ...] ) |

  73. FROM ( { <em class="replaceable"><code>partition_bound_expr</code></em> | MINVALUE | MAXVALUE } [, ...] )

  74.   TO ( { <em class="replaceable"><code>partition_bound_expr</code></em> | MINVALUE | MAXVALUE } [, ...] ) |

  75. WITH ( MODULUS <em class="replaceable"><code>numeric_literal</code></em>, REMAINDER <em class="replaceable"><code>numeric_literal</code></em> )

  76. 

  77. <span class="phrase"><em class="replaceable"><code>index_parameters</code></em> in <code class="literal">UNIQUE</code>, <code class="literal">PRIMARY KEY</code>, and <code class="literal">EXCLUDE</code> constraints are:</span>

  78. 

  79. [ INCLUDE ( <em class="replaceable"><code>column_name</code></em> [, ... ] ) ]

  80. [ WITH ( <em class="replaceable"><code>storage_parameter</code></em> [= <em class="replaceable"><code>value</code></em>] [, ... ] ) ]

  81. [ USING INDEX TABLESPACE <em class="replaceable"><code>tablespace_name</code></em> ]

  82. 

  83. <span class="phrase"><em class="replaceable"><code>exclude_element</code></em> in an <code class="literal">EXCLUDE</code> constraint is:</span>

  84. 

  85. { <em class="replaceable"><code>column_name</code></em> | ( <em class="replaceable"><code>expression</code></em> ) } [ <em class="replaceable"><code>opclass</code></em> ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ]

  86. </pre></div><div class="refsect1" id="SQL-CREATETABLE-DESCRIPTION"><h2>Description</h2><p>

  87.    <code class="command">CREATE TABLE</code> will create a new, initially empty table

  88.    in the current database. The table will be owned by the user issuing the

  89.    command.

  90.   </p><p>

  91.    If a schema name is given (for example, <code class="literal">CREATE TABLE

  92.    myschema.mytable ...</code>) then the table is created in the specified

  93.    schema.  Otherwise it is created in the current schema.  Temporary

  94.    tables exist in a special schema, so a schema name cannot be given

  95.    when creating a temporary table.  The name of the table must be

  96.    distinct from the name of any other table, sequence, index, view,

  97.    or foreign table in the same schema.

  98.   </p><p>

  99.    <code class="command">CREATE TABLE</code> also automatically creates a data

  100.    type that represents the composite type corresponding

  101.    to one row of the table.  Therefore, tables cannot have the same

  102.    name as any existing data type in the same schema.

  103.   </p><p>

  104.    The optional constraint clauses specify constraints (tests) that

  105.    new or updated rows must satisfy for an insert or update operation

  106.    to succeed.  A constraint is an SQL object that helps define the

  107.    set of valid values in the table in various ways.

  108.   </p><p>

  109.    There are two ways to define constraints: table constraints and

  110.    column constraints.  A column constraint is defined as part of a

  111.    column definition.  A table constraint definition is not tied to a

  112.    particular column, and it can encompass more than one column.

  113.    Every column constraint can also be written as a table constraint;

  114.    a column constraint is only a notational convenience for use when the

  115.    constraint only affects one column.

  116.   </p><p>

  117.    To be able to create a table, you must have <code class="literal">USAGE</code>

  118.    privilege on all column types or the type in the <code class="literal">OF</code>

  119.    clause, respectively.

  120.   </p></div><div class="refsect1" id="id-1.9.3.85.6"><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt id="SQL-CREATETABLE-TEMPORARY"><span class="term"><code class="literal">TEMPORARY</code> or <code class="literal">TEMP</code></span></dt><dd><p>

  121.       If specified, the table is created as a temporary table.

  122.       Temporary tables are automatically dropped at the end of a

  123.       session, or optionally at the end of the current transaction

  124.       (see <code class="literal">ON COMMIT</code> below).  Existing permanent

  125.       tables with the same name are not visible to the current session

  126.       while the temporary table exists, unless they are referenced

  127.       with schema-qualified names. Any indexes created on a temporary

  128.       table are automatically temporary as well.

  129.      </p><p>

  130.       The <a class="link" href="routine-vacuuming.html#AUTOVACUUM" title="24.1.6. The Autovacuum Daemon">autovacuum daemon</a> cannot

  131.       access and therefore cannot vacuum or analyze temporary tables.

  132.       For this reason, appropriate vacuum and analyze operations should be

  133.       performed via session SQL commands.  For example, if a temporary

  134.       table is going to be used in complex queries, it is wise to run

  135.       <code class="command">ANALYZE</code> on the temporary table after it is populated.

  136.      </p><p>

  137.       Optionally, <code class="literal">GLOBAL</code> or <code class="literal">LOCAL</code>

  138.       can be written before <code class="literal">TEMPORARY</code> or <code class="literal">TEMP</code>.

  139.       This presently makes no difference in <span class="productname">PostgreSQL</span>

  140.       and is deprecated; see

  141.       <a class="xref" href="sql-createtable.html#SQL-CREATETABLE-COMPATIBILITY" title="Compatibility">Compatibility</a>.

  142.      </p></dd><dt id="SQL-CREATETABLE-UNLOGGED"><span class="term"><code class="literal">UNLOGGED</code></span></dt><dd><p>

  143.       If specified, the table is created as an unlogged table.  Data written

  144.       to unlogged tables is not written to the write-ahead log (see <a class="xref" href="wal.html" title="Chapter 29. Reliability and the Write-Ahead Log">Chapter 29</a>), which makes them considerably faster than ordinary

  145.       tables.  However, they are not crash-safe: an unlogged table is

  146.       automatically truncated after a crash or unclean shutdown.  The contents

  147.       of an unlogged table are also not replicated to standby servers.

  148.       Any indexes created on an unlogged table are automatically unlogged as

  149.       well.

  150.      </p></dd><dt><span class="term"><code class="literal">IF NOT EXISTS</code></span></dt><dd><p>

  151.       Do not throw an error if a relation with the same name already exists.

  152.       A notice is issued in this case.  Note that there is no guarantee that

  153.       the existing relation is anything like the one that would have been

  154.       created.

  155.      </p></dd><dt><span class="term"><em class="replaceable"><code>table_name</code></em></span></dt><dd><p>

  156.       The name (optionally schema-qualified) of the table to be created.

  157.      </p></dd><dt><span class="term"><code class="literal">OF <em class="replaceable"><code>type_name</code></em></code></span></dt><dd><p>

  158.       Creates a <em class="firstterm">typed table</em>, which takes its

  159.       structure from the specified composite type (name optionally

  160.       schema-qualified).  A typed table is tied to its type; for

  161.       example the table will be dropped if the type is dropped

  162.       (with <code class="literal">DROP TYPE ... CASCADE</code>).

  163.      </p><p>

  164.       When a typed table is created, then the data types of the

  165.       columns are determined by the underlying composite type and are

  166.       not specified by the <code class="literal">CREATE TABLE</code> command.

  167.       But the <code class="literal">CREATE TABLE</code> command can add defaults

  168.       and constraints to the table and can specify storage parameters.

  169.      </p></dd><dt><span class="term"><em class="replaceable"><code>column_name</code></em></span></dt><dd><p>

  170.       The name of a column to be created in the new table.

  171.      </p></dd><dt><span class="term"><em class="replaceable"><code>data_type</code></em></span></dt><dd><p>

  172.       The data type of the column. This can include array

  173.       specifiers. For more information on the data types supported by

  174.       <span class="productname">PostgreSQL</span>, refer to <a class="xref" href="datatype.html" title="Chapter 8. Data Types">Chapter 8</a>.

  175.      </p></dd><dt><span class="term"><code class="literal">COLLATE <em class="replaceable"><code>collation</code></em></code></span></dt><dd><p>

  176.       The <code class="literal">COLLATE</code> clause assigns a collation to

  177.       the column (which must be of a collatable data type).

  178.       If not specified, the column data type's default collation is used.

  179.      </p></dd><dt><span class="term"><code class="literal">INHERITS ( <em class="replaceable"><code>parent_table</code></em> [, ... ] )</code></span></dt><dd><p>

  180.       The optional <code class="literal">INHERITS</code> clause specifies a list of

  181.       tables from which the new table automatically inherits all

  182.       columns.  Parent tables can be plain tables or foreign tables.

  183.      </p><p>

  184.       Use of <code class="literal">INHERITS</code> creates a persistent relationship

  185.       between the new child table and its parent table(s).  Schema

  186.       modifications to the parent(s) normally propagate to children

  187.       as well, and by default the data of the child table is included in

  188.       scans of the parent(s).

  189.      </p><p>

  190.       If the same column name exists in more than one parent

  191.       table, an error is reported unless the data types of the columns

  192.       match in each of the parent tables.  If there is no conflict,

  193.       then the duplicate columns are merged to form a single column in

  194.       the new table.  If the column name list of the new table

  195.       contains a column name that is also inherited, the data type must

  196.       likewise match the inherited column(s), and the column

  197.       definitions are merged into one.  If the

  198.       new table explicitly specifies a default value for the column,

  199.       this default overrides any defaults from inherited declarations

  200.       of the column.  Otherwise, any parents that specify default

  201.       values for the column must all specify the same default, or an

  202.       error will be reported.

  203.      </p><p>

  204.       <code class="literal">CHECK</code> constraints are merged in essentially the same way as

  205.       columns: if multiple parent tables and/or the new table definition

  206.       contain identically-named <code class="literal">CHECK</code> constraints, these

  207.       constraints must all have the same check expression, or an error will be

  208.       reported.  Constraints having the same name and expression will

  209.       be merged into one copy.  A constraint marked <code class="literal">NO INHERIT</code> in a

  210.       parent will not be considered.  Notice that an unnamed <code class="literal">CHECK</code>

  211.       constraint in the new table will never be merged, since a unique name

  212.       will always be chosen for it.

  213.      </p><p>

  214.       Column <code class="literal">STORAGE</code> settings are also copied from parent tables.

  215.      </p><p>

  216.       If a column in the parent table is an identity column, that property is

  217.       not inherited.  A column in the child table can be declared identity

  218.       column if desired.

  219.      </p></dd><dt><span class="term"><code class="literal">PARTITION BY { RANGE | LIST | HASH } ( { <em class="replaceable"><code>column_name</code></em> | ( <em class="replaceable"><code>expression</code></em> ) } [ <em class="replaceable"><code>opclass</code></em> ] [, ...] ) </code></span></dt><dd><p>

  220.       The optional <code class="literal">PARTITION BY</code> clause specifies a strategy

  221.       of partitioning the table.  The table thus created is called a

  222.       <em class="firstterm">partitioned</em> table.  The parenthesized list of

  223.       columns or expressions forms the <em class="firstterm">partition key</em>

  224.       for the table.  When using range or hash partitioning, the partition key

  225.       can include multiple columns or expressions (up to 32, but this limit can

  226.       be altered when building <span class="productname">PostgreSQL</span>), but for

  227.       list partitioning, the partition key must consist of a single column or

  228.       expression.

  229.      </p><p>

  230.       Range and list partitioning require a btree operator class, while hash

  231.       partitioning requires a hash operator class.  If no operator class is

  232.       specified explicitly, the default operator class of the appropriate

  233.       type will be used; if no default operator class exists, an error will

  234.       be raised.  When hash partitioning is used, the operator class used

  235.       must implement support function 2 (see <a class="xref" href="xindex.html#XINDEX-SUPPORT" title="37.16.3. Index Method Support Routines">Section 37.16.3</a>

  236.       for details).

  237.      </p><p>

  238.       A partitioned table is divided into sub-tables (called partitions),

  239.       which are created using separate <code class="literal">CREATE TABLE</code> commands.

  240.       The partitioned table is itself empty.  A data row inserted into the

  241.       table is routed to a partition based on the value of columns or

  242.       expressions in the partition key.  If no existing partition matches

  243.       the values in the new row, an error will be reported.

  244.      </p><p>

  245.       Partitioned tables do not support <code class="literal">EXCLUDE</code> constraints;

  246.       however, you can define these constraints on individual partitions.

  247.      </p><p>

  248.       See <a class="xref" href="ddl-partitioning.html" title="5.11. Table Partitioning">Section 5.11</a> for more discussion on table

  249.       partitioning.

  250.      </p></dd><dt id="SQL-CREATETABLE-PARTITION"><span class="term"><code class="literal">PARTITION OF <em class="replaceable"><code>parent_table</code></em> { FOR VALUES <em class="replaceable"><code>partition_bound_spec</code></em> | DEFAULT }</code></span></dt><dd><p>

  251.       Creates the table as a <em class="firstterm">partition</em> of the specified

  252.       parent table. The table can be created either as a partition for specific

  253.       values using <code class="literal">FOR VALUES</code> or as a default partition

  254.       using <code class="literal">DEFAULT</code>.  Any indexes, constraints and

  255.       user-defined row-level triggers that exist in the parent table are cloned

  256.       on the new partition.

  257.      </p><p>

  258.       The <em class="replaceable"><code>partition_bound_spec</code></em>

  259.       must correspond to the partitioning method and partition key of the

  260.       parent table, and must not overlap with any existing partition of that

  261.       parent.  The form with <code class="literal">IN</code> is used for list partitioning,

  262.       the form with <code class="literal">FROM</code> and <code class="literal">TO</code> is used

  263.       for range partitioning, and the form with <code class="literal">WITH</code> is used

  264.       for hash partitioning.

  265.      </p><p>

  266.       <em class="replaceable"><code>partition_bound_expr</code></em> is

  267.       any variable-free expression (subqueries, window functions, aggregate

  268.       functions, and set-returning functions are not allowed).  Its data type

  269.       must match the data type of the corresponding partition key column.

  270.       The expression is evaluated once at table creation time, so it can

  271.       even contain volatile expressions such as

  272.       <code class="literal"><code class="function">CURRENT_TIMESTAMP</code></code>.

  273.      </p><p>

  274.       When creating a list partition, <code class="literal">NULL</code> can be

  275.       specified to signify that the partition allows the partition key

  276.       column to be null.  However, there cannot be more than one such

  277.       list partition for a given parent table.  <code class="literal">NULL</code>

  278.       cannot be specified for range partitions.

  279.      </p><p>

  280.       When creating a range partition, the lower bound specified with

  281.       <code class="literal">FROM</code> is an inclusive bound, whereas the upper

  282.       bound specified with <code class="literal">TO</code> is an exclusive bound.

  283.       That is, the values specified in the <code class="literal">FROM</code> list

  284.       are valid values of the corresponding partition key columns for this

  285.       partition, whereas those in the <code class="literal">TO</code> list are

  286.       not.  Note that this statement must be understood according to the

  287.       rules of row-wise comparison (<a class="xref" href="functions-comparisons.html#ROW-WISE-COMPARISON" title="9.23.5. Row Constructor Comparison">Section 9.23.5</a>).

  288.       For example, given <code class="literal">PARTITION BY RANGE (x,y)</code>, a partition

  289.       bound <code class="literal">FROM (1, 2) TO (3, 4)</code>

  290.       allows <code class="literal">x=1</code> with any <code class="literal">y&gt;=2</code>,

  291.       <code class="literal">x=2</code> with any non-null <code class="literal">y</code>,

  292.       and <code class="literal">x=3</code> with any <code class="literal">y&lt;4</code>.

  293.      </p><p>

  294.       The special values <code class="literal">MINVALUE</code> and <code class="literal">MAXVALUE</code>

  295.       may be used when creating a range partition to indicate that there

  296.       is no lower or upper bound on the column's value. For example, a

  297.       partition defined using <code class="literal">FROM (MINVALUE) TO (10)</code> allows

  298.       any values less than 10, and a partition defined using

  299.       <code class="literal">FROM (10) TO (MAXVALUE)</code> allows any values greater than

  300.       or equal to 10.

  301.      </p><p>

  302.       When creating a range partition involving more than one column, it

  303.       can also make sense to use <code class="literal">MAXVALUE</code> as part of the lower

  304.       bound, and <code class="literal">MINVALUE</code> as part of the upper bound. For

  305.       example, a partition defined using

  306.       <code class="literal">FROM (0, MAXVALUE) TO (10, MAXVALUE)</code> allows any rows

  307.       where the first partition key column is greater than 0 and less than

  308.       or equal to 10. Similarly, a partition defined using

  309.       <code class="literal">FROM ('a', MINVALUE) TO ('b', MINVALUE)</code> allows any rows

  310.       where the first partition key column starts with "a".

  311.      </p><p>

  312.       Note that if <code class="literal">MINVALUE</code> or <code class="literal">MAXVALUE</code> is used for

  313.       one column of a partitioning bound, the same value must be used for all

  314.       subsequent columns.  For example, <code class="literal">(10, MINVALUE, 0)</code> is not

  315.       a valid bound; you should write <code class="literal">(10, MINVALUE, MINVALUE)</code>.

  316.      </p><p>

  317.       Also note that some element types, such as <code class="literal">timestamp</code>,

  318.       have a notion of "infinity", which is just another value that can

  319.       be stored. This is different from <code class="literal">MINVALUE</code> and

  320.       <code class="literal">MAXVALUE</code>, which are not real values that can be stored,

  321.       but rather they are ways of saying that the value is unbounded.

  322.       <code class="literal">MAXVALUE</code> can be thought of as being greater than any

  323.       other value, including "infinity" and <code class="literal">MINVALUE</code> as being

  324.       less than any other value, including "minus infinity". Thus the range

  325.       <code class="literal">FROM ('infinity') TO (MAXVALUE)</code> is not an empty range; it

  326.       allows precisely one value to be stored — "infinity".

  327.      </p><p>

  328.       If <code class="literal">DEFAULT</code> is specified, the table will be

  329.       created as the default partition of the parent table.  This option

  330.       is not available for hash-partitioned tables.  A partition key value

  331.       not fitting into any other partition of the given parent will be

  332.       routed to the default partition.

  333.      </p><p>

  334.       When a table has an existing <code class="literal">DEFAULT</code> partition and

  335.       a new partition is added to it, the default partition must

  336.       be scanned to verify that it does not contain any rows which properly

  337.       belong in the new partition.  If the default partition contains a

  338.       large number of rows, this may be slow.  The scan will be skipped if

  339.       the default partition is a foreign table or if it has a constraint which

  340.       proves that it cannot contain rows which should be placed in the new

  341.       partition.

  342.      </p><p>

  343.       When creating a hash partition, a modulus and remainder must be specified.

  344.       The modulus must be a positive integer, and the remainder must be a

  345.       non-negative integer less than the modulus.  Typically, when initially

  346.       setting up a hash-partitioned table, you should choose a modulus equal to

  347.       the number of partitions and assign every table the same modulus and a

  348.       different remainder (see examples, below).   However, it is not required

  349.       that every partition have the same modulus, only that every modulus which

  350.       occurs among the partitions of a hash-partitioned table is a factor of the

  351.       next larger modulus.  This allows the number of partitions to be increased

  352.       incrementally without needing to move all the data at once.  For example,

  353.       suppose you have a hash-partitioned table with 8 partitions, each of which

  354.       has modulus 8, but find it necessary to increase the number of partitions

  355.       to 16.  You can detach one of the modulus-8 partitions, create two new

  356.       modulus-16 partitions covering the same portion of the key space (one with

  357.       a remainder equal to the remainder of the detached partition, and the

  358.       other with a remainder equal to that value plus 8), and repopulate them

  359.       with data.  You can then repeat this -- perhaps at a later time -- for

  360.       each modulus-8 partition until none remain.  While this may still involve

  361.       a large amount of data movement at each step, it is still better than

  362.       having to create a whole new table and move all the data at once.

  363.      </p><p>

  364.       A partition must have the same column names and types as the partitioned

  365.       table to which it belongs. Modifications to the column names or types of

  366.       a partitioned table will automatically propagate to all partitions.

  367.       <code class="literal">CHECK</code> constraints will be inherited automatically by

  368.       every partition, but an individual partition may specify additional

  369.       <code class="literal">CHECK</code> constraints; additional constraints with the

  370.       same name and condition as in the parent will be merged with the parent

  371.       constraint.  Defaults may be specified separately for each partition.

  372.       But note that a partition's default value is not applied when inserting

  373.       a tuple through a partitioned table.

  374.      </p><p>

  375.       Rows inserted into a partitioned table will be automatically routed to

  376.       the correct partition.  If no suitable partition exists, an error will

  377.       occur.

  378.      </p><p>

  379.       Operations such as TRUNCATE which normally affect a table and all of its

  380.       inheritance children will cascade to all partitions, but may also be

  381.       performed on an individual partition.  Note that dropping a partition

  382.       with <code class="literal">DROP TABLE</code> requires taking an <code class="literal">ACCESS

  383.       EXCLUSIVE</code> lock on the parent table.

  384.      </p></dd><dt><span class="term"><code class="literal">LIKE <em class="replaceable"><code>source_table</code></em> [ <em class="replaceable"><code>like_option</code></em> ... ]</code></span></dt><dd><p>

  385.       The <code class="literal">LIKE</code> clause specifies a table from which

  386.       the new table automatically copies all column names, their data types,

  387.       and their not-null constraints.

  388.      </p><p>

  389.       Unlike <code class="literal">INHERITS</code>, the new table and original table

  390.       are completely decoupled after creation is complete.  Changes to the

  391.       original table will not be applied to the new table, and it is not

  392.       possible to include data of the new table in scans of the original

  393.       table.

  394.      </p><p>

  395.       Also unlike <code class="literal">INHERITS</code>, columns and

  396.       constraints copied by <code class="literal">LIKE</code> are not merged with similarly

  397.       named columns and constraints.

  398.       If the same name is specified explicitly or in another

  399.       <code class="literal">LIKE</code> clause, an error is signaled.

  400.      </p><p>

  401.       The optional <em class="replaceable"><code>like_option</code></em> clauses specify

  402.       which additional properties of the original table to copy.  Specifying

  403.       <code class="literal">INCLUDING</code> copies the property, specifying

  404.       <code class="literal">EXCLUDING</code> omits the property.

  405.       <code class="literal">EXCLUDING</code> is the default.  If multiple specifications

  406.       are made for the same kind of object, the last one is used.  The

  407.       available options are:

  408. 

  409.       </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">INCLUDING COMMENTS</code></span></dt><dd><p>

  410.           Comments for the copied columns, constraints, and indexes will be

  411.           copied.  The default behavior is to exclude comments, resulting in

  412.           the copied columns and constraints in the new table having no

  413.           comments.

  414.          </p></dd><dt><span class="term"><code class="literal">INCLUDING CONSTRAINTS</code></span></dt><dd><p>

  415.           <code class="literal">CHECK</code> constraints will be copied.  No distinction

  416.           is made between column constraints and table constraints.  Not-null

  417.           constraints are always copied to the new table.

  418.          </p></dd><dt><span class="term"><code class="literal">INCLUDING DEFAULTS</code></span></dt><dd><p>

  419.           Default expressions for the copied column definitions will be

  420.           copied.  Otherwise, default expressions are not copied, resulting in

  421.           the copied columns in the new table having null defaults.  Note that

  422.           copying defaults that call database-modification functions, such as

  423.           <code class="function">nextval</code>, may create a functional linkage

  424.           between the original and new tables.

  425.          </p></dd><dt><span class="term"><code class="literal">INCLUDING GENERATED</code></span></dt><dd><p>

  426.           Any generation expressions of copied column definitions will be

  427.           copied.  By default, new columns will be regular base columns.

  428.          </p></dd><dt><span class="term"><code class="literal">INCLUDING IDENTITY</code></span></dt><dd><p>

  429.           Any identity specifications of copied column definitions will be

  430.           copied.  A new sequence is created for each identity column of the

  431.           new table, separate from the sequences associated with the old

  432.           table.

  433.          </p></dd><dt><span class="term"><code class="literal">INCLUDING INDEXES</code></span></dt><dd><p>

  434.           Indexes, <code class="literal">PRIMARY KEY</code>, <code class="literal">UNIQUE</code>,

  435.           and <code class="literal">EXCLUDE</code> constraints on the original table

  436.           will be created on the new table.  Names for the new indexes and

  437.           constraints are chosen according to the default rules, regardless of

  438.           how the originals were named.  (This behavior avoids possible

  439.           duplicate-name failures for the new indexes.)

  440.          </p></dd><dt><span class="term"><code class="literal">INCLUDING STATISTICS</code></span></dt><dd><p>

  441.           Extended statistics are copied to the new table.

  442.          </p></dd><dt><span class="term"><code class="literal">INCLUDING STORAGE</code></span></dt><dd><p>

  443.           <code class="literal">STORAGE</code> settings for the copied column

  444.           definitions will be copied.  The default behavior is to exclude

  445.           <code class="literal">STORAGE</code> settings, resulting in the copied columns

  446.           in the new table having type-specific default settings.  For more on

  447.           <code class="literal">STORAGE</code> settings, see <a class="xref" href="storage-toast.html" title="68.2. TOAST">Section 68.2</a>.

  448.          </p></dd><dt><span class="term"><code class="literal">INCLUDING ALL</code></span></dt><dd><p>

  449.           <code class="literal">INCLUDING ALL</code> is an abbreviated form selecting

  450.           all the available individual options.  (It could be useful to write

  451.           individual <code class="literal">EXCLUDING</code> clauses after

  452.           <code class="literal">INCLUDING ALL</code> to select all but some specific

  453.           options.)

  454.          </p></dd></dl></div><p>

  455.      </p><p>

  456.       The <code class="literal">LIKE</code> clause can also be used to copy column

  457.       definitions from views, foreign tables, or composite types.

  458.       Inapplicable options (e.g., <code class="literal">INCLUDING INDEXES</code> from

  459.       a view) are ignored.

  460.      </p></dd><dt><span class="term"><code class="literal">CONSTRAINT <em class="replaceable"><code>constraint_name</code></em></code></span></dt><dd><p>

  461.       An optional name for a column or table constraint.  If the

  462.       constraint is violated, the constraint name is present in error messages,

  463.       so constraint names like <code class="literal">col must be positive</code> can be used

  464.       to communicate helpful constraint information to client applications.

  465.       (Double-quotes are needed to specify constraint names that contain spaces.)

  466.       If a constraint name is not specified, the system generates a name.

  467.      </p></dd><dt><span class="term"><code class="literal">NOT NULL</code></span></dt><dd><p>

  468.       The column is not allowed to contain null values.

  469.      </p></dd><dt><span class="term"><code class="literal">NULL</code></span></dt><dd><p>

  470.       The column is allowed to contain null values. This is the default.

  471.      </p><p>

  472.       This clause is only provided for compatibility with

  473.       non-standard SQL databases.  Its use is discouraged in new

  474.       applications.

  475.      </p></dd><dt><span class="term"><code class="literal">CHECK ( <em class="replaceable"><code>expression</code></em> ) [ NO INHERIT ] </code></span></dt><dd><p>

  476.       The <code class="literal">CHECK</code> clause specifies an expression producing a

  477.       Boolean result which new or updated rows must satisfy for an

  478.       insert or update operation to succeed.  Expressions evaluating

  479.       to TRUE or UNKNOWN succeed.  Should any row of an insert or

  480.       update operation produce a FALSE result, an error exception is

  481.       raised and the insert or update does not alter the database.  A

  482.       check constraint specified as a column constraint should

  483.       reference that column's value only, while an expression

  484.       appearing in a table constraint can reference multiple columns.

  485.      </p><p>

  486.       Currently, <code class="literal">CHECK</code> expressions cannot contain

  487.       subqueries nor refer to variables other than columns of the

  488.       current row (see <a class="xref" href="ddl-constraints.html#DDL-CONSTRAINTS-CHECK-CONSTRAINTS" title="5.4.1. Check Constraints">Section 5.4.1</a>).

  489.       The system column <code class="literal">tableoid</code>

  490.       may be referenced, but not any other system column.

  491.      </p><p>

  492.       A constraint marked with <code class="literal">NO INHERIT</code> will not propagate to

  493.       child tables.

  494.      </p><p>

  495.       When a table has multiple <code class="literal">CHECK</code> constraints,

  496.       they will be tested for each row in alphabetical order by name,

  497.       after checking <code class="literal">NOT NULL</code> constraints.

  498.       (<span class="productname">PostgreSQL</span> versions before 9.5 did not honor any

  499.       particular firing order for <code class="literal">CHECK</code> constraints.)

  500.      </p></dd><dt><span class="term"><code class="literal">DEFAULT

  501.     <em class="replaceable"><code>default_expr</code></em></code></span></dt><dd><p>

  502.       The <code class="literal">DEFAULT</code> clause assigns a default data value for

  503.       the column whose column definition it appears within.  The value

  504.       is any variable-free expression (in particular, cross-references

  505.       to other columns in the current table are not allowed).  Subqueries

  506.       are not allowed either.  The data type of the default expression must

  507.       match the data type of the column.

  508.      </p><p>

  509.       The default expression will be used in any insert operation that

  510.       does not specify a value for the column.  If there is no default

  511.       for a column, then the default is null.

  512.      </p></dd><dt><span class="term"><code class="literal">GENERATED ALWAYS AS ( <em class="replaceable"><code>generation_expr</code></em> ) STORED</code><a id="id-1.9.3.85.6.2.18.1.2" class="indexterm"></a></span></dt><dd><p>

  513.       This clause creates the column as a <em class="firstterm">generated

  514.       column</em>.  The column cannot be written to, and when read the

  515.       result of the specified expression will be returned.

  516.      </p><p>

  517.       The keyword <code class="literal">STORED</code> is required to signify that the

  518.       column will be computed on write and will be stored on disk.

  519.      </p><p>

  520.       The generation expression can refer to other columns in the table, but

  521.       not other generated columns.  Any functions and operators used must be

  522.       immutable.  References to other tables are not allowed.

  523.      </p></dd><dt><span class="term"><code class="literal">GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <em class="replaceable"><code>sequence_options</code></em> ) ]</code></span></dt><dd><p>

  524.       This clause creates the column as an <em class="firstterm">identity

  525.       column</em>.  It will have an implicit sequence attached to it

  526.       and the column in new rows will automatically have values from the

  527.       sequence assigned to it.

  528.      </p><p>

  529.       The clauses <code class="literal">ALWAYS</code> and <code class="literal">BY DEFAULT</code>

  530.       determine how the sequence value is given precedence over a

  531.       user-specified value in an <code class="command">INSERT</code> statement.

  532.       If <code class="literal">ALWAYS</code> is specified, a user-specified value is

  533.       only accepted if the <code class="command">INSERT</code> statement

  534.       specifies <code class="literal">OVERRIDING SYSTEM VALUE</code>.  If <code class="literal">BY

  535.       DEFAULT</code> is specified, then the user-specified value takes

  536.       precedence.  See <a class="xref" href="sql-insert.html" title="INSERT"><span class="refentrytitle">INSERT</span></a> for details.  (In

  537.       the <code class="command">COPY</code> command, user-specified values are always

  538.       used regardless of this setting.)

  539.      </p><p>

  540.       The optional <em class="replaceable"><code>sequence_options</code></em> clause can be

  541.       used to override the options of the sequence.

  542.       See <a class="xref" href="sql-createsequence.html" title="CREATE SEQUENCE"><span class="refentrytitle">CREATE SEQUENCE</span></a> for details.

  543.      </p></dd><dt><span class="term"><code class="literal">UNIQUE</code> (column constraint)<br /></span><span class="term"><code class="literal">UNIQUE ( <em class="replaceable"><code>column_name</code></em> [, ... ] )</code>

  544.     [<span class="optional"> INCLUDE ( <em class="replaceable"><code>column_name</code></em> [, ...]) </span>] (table constraint)</span></dt><dd><p>

  545.       The <code class="literal">UNIQUE</code> constraint specifies that a

  546.       group of one or more columns of a table can contain

  547.       only unique values. The behavior of the unique table constraint

  548.       is the same as that for column constraints, with the additional

  549.       capability to span multiple columns.

  550.      </p><p>

  551.       For the purpose of a unique constraint, null values are not

  552.       considered equal.

  553.      </p><p>

  554.       Each unique table constraint must name a set of columns that is

  555.       different from the set of columns named by any other unique or

  556.       primary key constraint defined for the table.  (Otherwise it

  557.       would just be the same constraint listed twice.)

  558.      </p><p>

  559.       When establishing a unique constraint for a multi-level partition

  560.       hierarchy, all the columns in the partition key of the target

  561.       partitioned table, as well as those of all its descendant partitioned

  562.       tables, must be included in the constraint definition.

  563.      </p><p>

  564.       Adding a unique constraint will automatically create a unique btree

  565.       index on the column or group of columns used in the constraint.

  566.       The optional clause <code class="literal">INCLUDE</code> adds to that index

  567.       one or more columns on which the uniqueness is not enforced.

  568.       Note that although the constraint is not enforced on the included columns,

  569.       it still depends on them.  Consequently, some operations on these columns

  570.       (e.g. <code class="literal">DROP COLUMN</code>) can cause cascaded constraint and

  571.       index deletion.

  572.      </p></dd><dt><span class="term"><code class="literal">PRIMARY KEY</code> (column constraint)<br /></span><span class="term"><code class="literal">PRIMARY KEY ( <em class="replaceable"><code>column_name</code></em> [, ... ] )</code>

  573.     [<span class="optional"> INCLUDE ( <em class="replaceable"><code>column_name</code></em> [, ...]) </span>] (table constraint)</span></dt><dd><p>

  574.       The <code class="literal">PRIMARY KEY</code> constraint specifies that a column or

  575.       columns of a table can contain only unique (non-duplicate), nonnull

  576.       values. Only one primary key can be specified for a table, whether as a

  577.       column constraint or a table constraint.

  578.      </p><p>

  579.       The primary key constraint should name a set of columns that is

  580.       different from the set of columns named by any unique

  581.       constraint defined for the same table.  (Otherwise, the unique

  582.       constraint is redundant and will be discarded.)

  583.      </p><p>

  584.       <code class="literal">PRIMARY KEY</code> enforces the same data constraints as

  585.       a combination of <code class="literal">UNIQUE</code> and <code class="literal">NOT NULL</code>, but

  586.       identifying a set of columns as the primary key also provides metadata

  587.       about the design of the schema, since a primary key implies that other

  588.       tables can rely on this set of columns as a unique identifier for rows.

  589.      </p><p>

  590.       <code class="literal">PRIMARY KEY</code> constraints share the restrictions that

  591.       <code class="literal">UNIQUE</code> constraints have when placed on partitioned

  592.       tables.

  593.      </p><p>

  594.       Adding a <code class="literal">PRIMARY KEY</code> constraint will automatically

  595.       create a unique btree index on the column or group of columns used in the

  596.       constraint.  The optional <code class="literal">INCLUDE</code> clause allows a list

  597.       of columns to be specified which will be included in the non-key portion

  598.       of the index.  Although uniqueness is not enforced on the included columns,

  599.       the constraint still depends on them. Consequently, some operations on the

  600.       included columns (e.g. <code class="literal">DROP COLUMN</code>) can cause cascaded

  601.       constraint and index deletion.

  602.      </p></dd><dt id="SQL-CREATETABLE-EXCLUDE"><span class="term"><code class="literal">EXCLUDE [ USING <em class="replaceable"><code>index_method</code></em> ] ( <em class="replaceable"><code>exclude_element</code></em> WITH <em class="replaceable"><code>operator</code></em> [, ... ] ) <em class="replaceable"><code>index_parameters</code></em> [ WHERE ( <em class="replaceable"><code>predicate</code></em> ) ]</code></span></dt><dd><p>

  603.       The <code class="literal">EXCLUDE</code> clause defines an exclusion

  604.       constraint, which guarantees that if

  605.       any two rows are compared on the specified column(s) or

  606.       expression(s) using the specified operator(s), not all of these

  607.       comparisons will return <code class="literal">TRUE</code>.  If all of the

  608.       specified operators test for equality, this is equivalent to a

  609.       <code class="literal">UNIQUE</code> constraint, although an ordinary unique constraint

  610.       will be faster.  However, exclusion constraints can specify

  611.       constraints that are more general than simple equality.

  612.       For example, you can specify a constraint that

  613.       no two rows in the table contain overlapping circles

  614.       (see <a class="xref" href="datatype-geometric.html" title="8.8. Geometric Types">Section 8.8</a>) by using the

  615.       <code class="literal">&amp;&amp;</code> operator.

  616.      </p><p>

  617.       Exclusion constraints are implemented using

  618.       an index, so each specified operator must be associated with an

  619.       appropriate operator class

  620.       (see <a class="xref" href="indexes-opclass.html" title="11.10. Operator Classes and Operator Families">Section 11.10</a>) for the index access

  621.       method <em class="replaceable"><code>index_method</code></em>.

  622.       The operators are required to be commutative.

  623.       Each <em class="replaceable"><code>exclude_element</code></em>

  624.       can optionally specify an operator class and/or ordering options;

  625.       these are described fully under

  626.       <a class="xref" href="sql-createindex.html" title="CREATE INDEX"><span class="refentrytitle">CREATE INDEX</span></a>.

  627.      </p><p>

  628.       The access method must support <code class="literal">amgettuple</code> (see <a class="xref" href="indexam.html" title="Chapter 61. Index Access Method Interface Definition">Chapter 61</a>); at present this means <acronym class="acronym">GIN</acronym>

  629.       cannot be used.  Although it's allowed, there is little point in using

  630.       B-tree or hash indexes with an exclusion constraint, because this

  631.       does nothing that an ordinary unique constraint doesn't do better.

  632.       So in practice the access method will always be <acronym class="acronym">GiST</acronym> or

  633.       <acronym class="acronym">SP-GiST</acronym>.

  634.      </p><p>

  635.       The <em class="replaceable"><code>predicate</code></em> allows you to specify an

  636.       exclusion constraint on a subset of the table; internally this creates a

  637.       partial index. Note that parentheses are required around the predicate.

  638.      </p></dd><dt><span class="term"><code class="literal">REFERENCES <em class="replaceable"><code>reftable</code></em> [ ( <em class="replaceable"><code>refcolumn</code></em> ) ] [ MATCH <em class="replaceable"><code>matchtype</code></em> ] [ ON DELETE <em class="replaceable"><code>referential_action</code></em> ] [ ON UPDATE <em class="replaceable"><code>referential_action</code></em> ]</code> (column constraint)<br /></span><span class="term"><code class="literal">FOREIGN KEY ( <em class="replaceable"><code>column_name</code></em> [, ... ] )

  639.     REFERENCES <em class="replaceable"><code>reftable</code></em> [ ( <em class="replaceable"><code>refcolumn</code></em> [, ... ] ) ]

  640.     [ MATCH <em class="replaceable"><code>matchtype</code></em> ]

  641.     [ ON DELETE <em class="replaceable"><code>referential_action</code></em> ]

  642.     [ ON UPDATE <em class="replaceable"><code>referential_action</code></em> ]</code>

  643.     (table constraint)</span></dt><dd><p>

  644.       These clauses specify a foreign key constraint, which requires

  645.       that a group of one or more columns of the new table must only

  646.       contain values that match values in the referenced

  647.       column(s) of some row of the referenced table.  If the <em class="replaceable"><code>refcolumn</code></em> list is omitted, the

  648.       primary key of the <em class="replaceable"><code>reftable</code></em>

  649.       is used.  The referenced columns must be the columns of a non-deferrable

  650.       unique or primary key constraint in the referenced table.  The user

  651.       must have <code class="literal">REFERENCES</code> permission on the referenced table

  652.       (either the whole table, or the specific referenced columns).  The

  653.       addition of a foreign key constraint requires a

  654.       <code class="literal">SHARE ROW EXCLUSIVE</code> lock on the referenced table.

  655.       Note that foreign key constraints cannot be defined between temporary

  656.       tables and permanent tables.

  657.      </p><p>

  658.       A value inserted into the referencing column(s) is matched against the

  659.       values of the referenced table and referenced columns using the

  660.       given match type.  There are three match types: <code class="literal">MATCH

  661.       FULL</code>, <code class="literal">MATCH PARTIAL</code>, and <code class="literal">MATCH

  662.       SIMPLE</code> (which is the default).  <code class="literal">MATCH

  663.       FULL</code> will not allow one column of a multicolumn foreign key

  664.       to be null unless all foreign key columns are null; if they are all

  665.       null, the row is not required to have a match in the referenced table.

  666.       <code class="literal">MATCH SIMPLE</code> allows any of the foreign key columns

  667.       to be null; if any of them are null, the row is not required to have a

  668.       match in the referenced table.

  669.       <code class="literal">MATCH PARTIAL</code> is not yet implemented.

  670.       (Of course, <code class="literal">NOT NULL</code> constraints can be applied to the

  671.       referencing column(s) to prevent these cases from arising.)

  672.      </p><p>

  673.       In addition, when the data in the referenced columns is changed,

  674.       certain actions are performed on the data in this table's

  675.       columns.  The <code class="literal">ON DELETE</code> clause specifies the

  676.       action to perform when a referenced row in the referenced table is

  677.       being deleted.  Likewise, the <code class="literal">ON UPDATE</code>

  678.       clause specifies the action to perform when a referenced column

  679.       in the referenced table is being updated to a new value. If the

  680.       row is updated, but the referenced column is not actually

  681.       changed, no action is done. Referential actions other than the

  682.       <code class="literal">NO ACTION</code> check cannot be deferred, even if

  683.       the constraint is declared deferrable. There are the following possible

  684.       actions for each clause:

  685. 

  686.       </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">NO ACTION</code></span></dt><dd><p>

  687.           Produce an error indicating that the deletion or update

  688.           would create a foreign key constraint violation.

  689.           If the constraint is deferred, this

  690.           error will be produced at constraint check time if there still

  691.           exist any referencing rows.  This is the default action.

  692.          </p></dd><dt><span class="term"><code class="literal">RESTRICT</code></span></dt><dd><p>

  693.           Produce an error indicating that the deletion or update

  694.           would create a foreign key constraint violation.

  695.           This is the same as <code class="literal">NO ACTION</code> except that

  696.           the check is not deferrable.

  697.          </p></dd><dt><span class="term"><code class="literal">CASCADE</code></span></dt><dd><p>

  698.           Delete any rows referencing the deleted row, or update the

  699.           values of the referencing column(s) to the new values of the

  700.           referenced columns, respectively.

  701.          </p></dd><dt><span class="term"><code class="literal">SET NULL</code></span></dt><dd><p>

  702.           Set the referencing column(s) to null.

  703.          </p></dd><dt><span class="term"><code class="literal">SET DEFAULT</code></span></dt><dd><p>

  704.           Set the referencing column(s) to their default values.

  705.           (There must be a row in the referenced table matching the default

  706.           values, if they are not null, or the operation will fail.)

  707.          </p></dd></dl></div><p>

  708.      </p><p>

  709.       If the referenced column(s) are changed frequently, it might be wise to

  710.       add an index to the referencing column(s) so that referential actions

  711.       associated with the foreign key constraint can be performed more

  712.       efficiently.

  713.      </p></dd><dt><span class="term"><code class="literal">DEFERRABLE</code><br /></span><span class="term"><code class="literal">NOT DEFERRABLE</code></span></dt><dd><p>

  714.       This controls whether the constraint can be deferred.  A

  715.       constraint that is not deferrable will be checked immediately

  716.       after every command.  Checking of constraints that are

  717.       deferrable can be postponed until the end of the transaction

  718.       (using the <a class="xref" href="sql-set-constraints.html" title="SET CONSTRAINTS"><span class="refentrytitle">SET CONSTRAINTS</span></a> command).

  719.       <code class="literal">NOT DEFERRABLE</code> is the default.

  720.       Currently, only <code class="literal">UNIQUE</code>, <code class="literal">PRIMARY KEY</code>,

  721.       <code class="literal">EXCLUDE</code>, and

  722.       <code class="literal">REFERENCES</code> (foreign key) constraints accept this

  723.       clause.  <code class="literal">NOT NULL</code> and <code class="literal">CHECK</code> constraints are not

  724.       deferrable.  Note that deferrable constraints cannot be used as

  725.       conflict arbitrators in an <code class="command">INSERT</code> statement that

  726.       includes an <code class="literal">ON CONFLICT DO UPDATE</code> clause.

  727.      </p></dd><dt><span class="term"><code class="literal">INITIALLY IMMEDIATE</code><br /></span><span class="term"><code class="literal">INITIALLY DEFERRED</code></span></dt><dd><p>

  728.       If a constraint is deferrable, this clause specifies the default

  729.       time to check the constraint.  If the constraint is

  730.       <code class="literal">INITIALLY IMMEDIATE</code>, it is checked after each

  731.       statement. This is the default.  If the constraint is

  732.       <code class="literal">INITIALLY DEFERRED</code>, it is checked only at the

  733.       end of the transaction.  The constraint check time can be

  734.       altered with the <a class="xref" href="sql-set-constraints.html" title="SET CONSTRAINTS"><span class="refentrytitle">SET CONSTRAINTS</span></a> command.

  735.      </p></dd><dt id="SQL-CREATETABLE-METHOD"><span class="term"><code class="literal">USING <em class="replaceable"><code>method</code></em></code></span></dt><dd><p>

  736.       This optional clause specifies the table access method to use to store

  737.       the contents for the new table; the method needs be an access method of

  738.       type <code class="literal">TABLE</code>. See <a class="xref" href="tableam.html" title="Chapter 60. Table Access Method Interface Definition">Chapter 60</a> for more

  739.       information.  If this option is not specified, the default table access

  740.       method is chosen for the new table. See <a class="xref" href="runtime-config-client.html#GUC-DEFAULT-TABLE-ACCESS-METHOD">default_table_access_method</a> for more information.

  741.      </p></dd><dt><span class="term"><code class="literal">WITH ( <em class="replaceable"><code>storage_parameter</code></em> [= <em class="replaceable"><code>value</code></em>] [, ... ] )</code></span></dt><dd><p>

  742.       This clause specifies optional storage parameters for a table or index;

  743.       see <a class="xref" href="sql-createtable.html#SQL-CREATETABLE-STORAGE-PARAMETERS" title="Storage Parameters">Storage Parameters</a> for more

  744.       information.  For backward-compatibility the <code class="literal">WITH</code>

  745.       clause for a table can also include <code class="literal">OIDS=FALSE</code> to

  746.       specify that rows of the new table should not contain OIDs (object

  747.       identifiers), <code class="literal">OIDS=TRUE</code> is not supported anymore.

  748.      </p></dd><dt><span class="term"><code class="literal">WITHOUT OIDS</code></span></dt><dd><p>

  749.       This is backward-compatible syntax for declaring a table

  750.       <code class="literal">WITHOUT OIDS</code>, creating a table <code class="literal">WITH

  751.       OIDS</code> is not supported anymore.

  752.      </p></dd><dt><span class="term"><code class="literal">ON COMMIT</code></span></dt><dd><p>

  753.       The behavior of temporary tables at the end of a transaction

  754.       block can be controlled using <code class="literal">ON COMMIT</code>.

  755.       The three options are:

  756. 

  757.       </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">PRESERVE ROWS</code></span></dt><dd><p>

  758.           No special action is taken at the ends of transactions.

  759.           This is the default behavior.

  760.          </p></dd><dt><span class="term"><code class="literal">DELETE ROWS</code></span></dt><dd><p>

  761.           All rows in the temporary table will be deleted at the end

  762.           of each transaction block.  Essentially, an automatic <a class="xref" href="sql-truncate.html" title="TRUNCATE"><span class="refentrytitle">TRUNCATE</span></a> is done

  763.           at each commit.  When used on a partitioned table, this

  764.           is not cascaded to its partitions.

  765.          </p></dd><dt><span class="term"><code class="literal">DROP</code></span></dt><dd><p>

  766.           The temporary table will be dropped at the end of the current

  767.           transaction block.  When used on a partitioned table, this action

  768.           drops its partitions and when used on tables with inheritance

  769.           children, it drops the dependent children.

  770.          </p></dd></dl></div></dd><dt id="SQL-CREATETABLE-TABLESPACE"><span class="term"><code class="literal">TABLESPACE <em class="replaceable"><code>tablespace_name</code></em></code></span></dt><dd><p>

  771.       The <em class="replaceable"><code>tablespace_name</code></em> is the name

  772.       of the tablespace in which the new table is to be created.

  773.       If not specified,

  774.       <a class="xref" href="runtime-config-client.html#GUC-DEFAULT-TABLESPACE">default_tablespace</a> is consulted, or

  775.       <a class="xref" href="runtime-config-client.html#GUC-TEMP-TABLESPACES">temp_tablespaces</a> if the table is temporary.  For

  776.       partitioned tables, since no storage is required for the table itself,

  777.       the tablespace specified overrides <code class="literal">default_tablespace</code>

  778.       as the default tablespace to use for any newly created partitions when no

  779.       other tablespace is explicitly specified.

  780.      </p></dd><dt><span class="term"><code class="literal">USING INDEX TABLESPACE <em class="replaceable"><code>tablespace_name</code></em></code></span></dt><dd><p>

  781.       This clause allows selection of the tablespace in which the index

  782.       associated with a <code class="literal">UNIQUE</code>, <code class="literal">PRIMARY

  783.       KEY</code>, or <code class="literal">EXCLUDE</code> constraint will be created.

  784.       If not specified,

  785.       <a class="xref" href="runtime-config-client.html#GUC-DEFAULT-TABLESPACE">default_tablespace</a> is consulted, or

  786.       <a class="xref" href="runtime-config-client.html#GUC-TEMP-TABLESPACES">temp_tablespaces</a> if the table is temporary.

  787.      </p></dd></dl></div><div class="refsect2" id="SQL-CREATETABLE-STORAGE-PARAMETERS"><h3>Storage Parameters</h3><a id="id-1.9.3.85.6.3.2" class="indexterm"></a><p>

  788.     The <code class="literal">WITH</code> clause can specify <em class="firstterm">storage parameters</em>

  789.     for tables, and for indexes associated with a <code class="literal">UNIQUE</code>,

  790.     <code class="literal">PRIMARY KEY</code>, or <code class="literal">EXCLUDE</code> constraint.

  791.     Storage parameters for

  792.     indexes are documented in <a class="xref" href="sql-createindex.html" title="CREATE INDEX"><span class="refentrytitle">CREATE INDEX</span></a>.

  793.     The storage parameters currently

  794.     available for tables are listed below.  For many of these parameters, as

  795.     shown, there is an additional parameter with the same name prefixed with

  796.     <code class="literal">toast.</code>, which controls the behavior of the

  797.     table's secondary <acronym class="acronym">TOAST</acronym> table, if any

  798.     (see <a class="xref" href="storage-toast.html" title="68.2. TOAST">Section 68.2</a> for more information about TOAST).

  799.     If a table parameter value is set and the

  800.     equivalent <code class="literal">toast.</code> parameter is not, the TOAST table

  801.     will use the table's parameter value.

  802.     Specifying these parameters for partitioned tables is not supported,

  803.     but you may specify them for individual leaf partitions.

  804.    </p><div class="variablelist"><dl class="variablelist"><dt id="RELOPTION-FILLFACTOR"><span class="term"><code class="varname">fillfactor</code> (<code class="type">integer</code>)

  805.     <a id="id-1.9.3.85.6.3.4.1.1.3" class="indexterm"></a>

  806.     </span></dt><dd><p>

  807.       The fillfactor for a table is a percentage between 10 and 100.

  808.       100 (complete packing) is the default.  When a smaller fillfactor

  809.       is specified, <code class="command">INSERT</code> operations pack table pages only

  810.       to the indicated percentage; the remaining space on each page is

  811.       reserved for updating rows on that page.  This gives <code class="command">UPDATE</code>

  812.       a chance to place the updated copy of a row on the same page as the

  813.       original, which is more efficient than placing it on a different page.

  814.       For a table whose entries are never updated, complete packing is the

  815.       best choice, but in heavily updated tables smaller fillfactors are

  816.       appropriate.  This parameter cannot be set for TOAST tables.

  817.      </p></dd><dt id="RELOPTION-TOAST-TUPLE-TARGET"><span class="term"><code class="literal">toast_tuple_target</code> (<code class="type">integer</code>)

  818.     <a id="id-1.9.3.85.6.3.4.2.1.3" class="indexterm"></a>

  819.     </span></dt><dd><p>

  820.       The toast_tuple_target specifies the minimum tuple length required before

  821.       we try to move long column values into TOAST tables, and is also the

  822.       target length we try to reduce the length below once toasting begins.

  823.       This only affects columns marked as either External or Extended

  824.       and applies only to new tuples - there is no effect on existing rows.

  825.       By default this parameter is set to allow at least 4 tuples per block,

  826.       which with the default blocksize will be 2040 bytes. Valid values are

  827.       between 128 bytes and the (blocksize - header), by default 8160 bytes.

  828.       Changing this value may not be useful for very short or very long rows.

  829.       Note that the default setting is often close to optimal, and

  830.       it is possible that setting this parameter could have negative

  831.       effects in some cases.

  832.       This parameter cannot be set for TOAST tables.

  833.      </p></dd><dt id="RELOPTION-PARALLEL-WORKERS"><span class="term"><code class="literal">parallel_workers</code> (<code class="type">integer</code>)

  834.      <a id="id-1.9.3.85.6.3.4.3.1.3" class="indexterm"></a>

  835.     </span></dt><dd><p>

  836.       This sets the number of workers that should be used to assist a parallel

  837.       scan of this table.  If not set, the system will determine a value based

  838.       on the relation size.  The actual number of workers chosen by the planner

  839.       or by utility statements that use parallel scans may be less, for example

  840.       due to the setting of <a class="xref" href="runtime-config-resource.html#GUC-MAX-WORKER-PROCESSES">max_worker_processes</a>.

  841.      </p></dd><dt id="RELOPTION-AUTOVACUUM-ENABLED"><span class="term"><code class="literal">autovacuum_enabled</code>, <code class="literal">toast.autovacuum_enabled</code> (<code class="type">boolean</code>)

  842.     <a id="id-1.9.3.85.6.3.4.4.1.4" class="indexterm"></a>

  843.     </span></dt><dd><p>

  844.      Enables or disables the autovacuum daemon for a particular table.

  845.      If true, the autovacuum daemon will perform automatic <code class="command">VACUUM</code>

  846.      and/or <code class="command">ANALYZE</code> operations on this table following the rules

  847.      discussed in <a class="xref" href="routine-vacuuming.html#AUTOVACUUM" title="24.1.6. The Autovacuum Daemon">Section 24.1.6</a>.

  848.      If false, this table will not be autovacuumed, except to prevent

  849.      transaction ID wraparound. See <a class="xref" href="routine-vacuuming.html#VACUUM-FOR-WRAPAROUND" title="24.1.5. Preventing Transaction ID Wraparound Failures">Section 24.1.5</a> for

  850.      more about wraparound prevention.

  851.      Note that the autovacuum daemon does not run at all (except to prevent

  852.      transaction ID wraparound) if the <a class="xref" href="runtime-config-autovacuum.html#GUC-AUTOVACUUM">autovacuum</a>

  853.      parameter is false; setting individual tables' storage parameters does

  854.      not override that.  Therefore there is seldom much point in explicitly

  855.      setting this storage parameter to <code class="literal">true</code>, only

  856.      to <code class="literal">false</code>.

  857.      </p></dd><dt id="RELOPTION-VACUUM-INDEX-CLEANUP"><span class="term"><code class="literal">vacuum_index_cleanup</code>, <code class="literal">toast.vacuum_index_cleanup</code> (<code class="type">boolean</code>)

  858.     <a id="id-1.9.3.85.6.3.4.5.1.4" class="indexterm"></a>

  859.     </span></dt><dd><p>

  860.       Enables or disables index cleanup when <code class="command">VACUUM</code> is

  861.       run on this table.  The default value is <code class="literal">true</code>.

  862.       Disabling index cleanup can speed up <code class="command">VACUUM</code> very

  863.       significantly, but may also lead to severely bloated indexes if table

  864.       modifications are frequent.  The <code class="literal">INDEX_CLEANUP</code>

  865.       parameter of <a class="xref" href="sql-vacuum.html" title="VACUUM"><span class="refentrytitle">VACUUM</span></a>, if specified, overrides

  866.       the value of this option.

  867.      </p></dd><dt id="RELOPTION-VACUUM-TRUNCATE"><span class="term"><code class="literal">vacuum_truncate</code>, <code class="literal">toast.vacuum_truncate</code> (<code class="type">boolean</code>)

  868.     <a id="id-1.9.3.85.6.3.4.6.1.4" class="indexterm"></a>

  869.     </span></dt><dd><p>

  870.       Enables or disables vacuum to try to truncate off any empty pages

  871.       at the end of this table. The default value is <code class="literal">true</code>.

  872.       If <code class="literal">true</code>, <code class="command">VACUUM</code> and

  873.       autovacuum do the truncation and the disk space for

  874.       the truncated pages is returned to the operating system.

  875.       Note that the truncation requires <code class="literal">ACCESS EXCLUSIVE</code>

  876.       lock on the table. The <code class="literal">TRUNCATE</code> parameter

  877.       of <a class="xref" href="sql-vacuum.html" title="VACUUM"><span class="refentrytitle">VACUUM</span></a>, if specified, overrides the value

  878.       of this option.

  879.      </p></dd><dt id="RELOPTION-AUTOVACUUM-VACUUM-THRESHOLD"><span class="term"><code class="literal">autovacuum_vacuum_threshold</code>, <code class="literal">toast.autovacuum_vacuum_threshold</code> (<code class="type">integer</code>)

  880.     <a id="id-1.9.3.85.6.3.4.7.1.4" class="indexterm"></a>

  881.     </span></dt><dd><p>

  882.       Per-table value for <a class="xref" href="runtime-config-autovacuum.html#GUC-AUTOVACUUM-VACUUM-THRESHOLD">autovacuum_vacuum_threshold</a>

  883.       parameter.

  884.      </p></dd><dt id="RELOPTION-AUTOVACUUM-VAUUM-SCALE-FACTOR"><span class="term"><code class="literal">autovacuum_vacuum_scale_factor</code>, <code class="literal">toast.autovacuum_vacuum_scale_factor</code> (<code class="type">floating point</code>)

  885.     <a id="id-1.9.3.85.6.3.4.8.1.4" class="indexterm"></a>

  886.     </span></dt><dd><p>

  887.       Per-table value for <a class="xref" href="runtime-config-autovacuum.html#GUC-AUTOVACUUM-VACUUM-SCALE-FACTOR">autovacuum_vacuum_scale_factor</a>

  888.       parameter.

  889.      </p></dd><dt id="RELOPTION-AUTOVACUUM-ANALYZE-THRESHOLD"><span class="term"><code class="literal">autovacuum_analyze_threshold</code> (<code class="type">integer</code>)

  890.     <a id="id-1.9.3.85.6.3.4.9.1.3" class="indexterm"></a>

  891.     </span></dt><dd><p>

  892.       Per-table value for <a class="xref" href="runtime-config-autovacuum.html#GUC-AUTOVACUUM-ANALYZE-THRESHOLD">autovacuum_analyze_threshold</a>

  893.       parameter.

  894.      </p></dd><dt id="RELOPTION-AUTOVACUUM-ANALYZE-SCALE-FACTOR"><span class="term"><code class="literal">autovacuum_analyze_scale_factor</code> (<code class="type">floating point</code>)

  895.     <a id="id-1.9.3.85.6.3.4.10.1.3" class="indexterm"></a>

  896.     </span></dt><dd><p>

  897.       Per-table value for <a class="xref" href="runtime-config-autovacuum.html#GUC-AUTOVACUUM-ANALYZE-SCALE-FACTOR">autovacuum_analyze_scale_factor</a>

  898.       parameter.

  899.      </p></dd><dt id="RELOPTION-AUTOVACUUM-VACUUM-COST-DELAY"><span class="term"><code class="literal">autovacuum_vacuum_cost_delay</code>, <code class="literal">toast.autovacuum_vacuum_cost_delay</code> (<code class="type">floating point</code>)

  900.     <a id="id-1.9.3.85.6.3.4.11.1.4" class="indexterm"></a>

  901.     </span></dt><dd><p>

  902.       Per-table value for <a class="xref" href="runtime-config-autovacuum.html#GUC-AUTOVACUUM-VACUUM-COST-DELAY">autovacuum_vacuum_cost_delay</a>

  903.       parameter.

  904.      </p></dd><dt id="RELOPTION-AUTOVACUUM-VAUUM-COST-LIMIT"><span class="term"><code class="literal">autovacuum_vacuum_cost_limit</code>, <code class="literal">toast.autovacuum_vacuum_cost_limit</code> (<code class="type">integer</code>)

  905.     <a id="id-1.9.3.85.6.3.4.12.1.4" class="indexterm"></a>

  906.     </span></dt><dd><p>

  907.       Per-table value for <a class="xref" href="runtime-config-autovacuum.html#GUC-AUTOVACUUM-VACUUM-COST-LIMIT">autovacuum_vacuum_cost_limit</a>

  908.       parameter.

  909.      </p></dd><dt id="RELOPTION-AUTOVACUUM-FREEZE-MIN-AGE"><span class="term"><code class="literal">autovacuum_freeze_min_age</code>, <code class="literal">toast.autovacuum_freeze_min_age</code> (<code class="type">integer</code>)

  910.     <a id="id-1.9.3.85.6.3.4.13.1.4" class="indexterm"></a>

  911.     </span></dt><dd><p>

  912.       Per-table value for <a class="xref" href="runtime-config-client.html#GUC-VACUUM-FREEZE-MIN-AGE">vacuum_freeze_min_age</a>

  913.       parameter.  Note that autovacuum will ignore

  914.       per-table <code class="literal">autovacuum_freeze_min_age</code> parameters that are

  915.       larger than half the

  916.       system-wide <a class="xref" href="runtime-config-autovacuum.html#GUC-AUTOVACUUM-FREEZE-MAX-AGE">autovacuum_freeze_max_age</a> setting.

  917.      </p></dd><dt id="RELOPTION-AUTOVACUUM-FREEZE-MAX-AGE"><span class="term"><code class="literal">autovacuum_freeze_max_age</code>, <code class="literal">toast.autovacuum_freeze_max_age</code> (<code class="type">integer</code>)

  918.     <a id="id-1.9.3.85.6.3.4.14.1.4" class="indexterm"></a>

  919.     </span></dt><dd><p>

  920.       Per-table value for <a class="xref" href="runtime-config-autovacuum.html#GUC-AUTOVACUUM-FREEZE-MAX-AGE">autovacuum_freeze_max_age</a>

  921.       parameter.  Note that autovacuum will ignore

  922.       per-table <code class="literal">autovacuum_freeze_max_age</code> parameters that are

  923.       larger than the system-wide setting (it can only be set smaller).

  924.      </p></dd><dt id="RELOPTION-AUTOVACUUM-FREEZE-TABLE-AGE"><span class="term"><code class="literal">autovacuum_freeze_table_age</code>, <code class="literal">toast.autovacuum_freeze_table_age</code> (<code class="type">integer</code>)

  925.     <a id="id-1.9.3.85.6.3.4.15.1.4" class="indexterm"></a>

  926.     </span></dt><dd><p>

  927.       Per-table value for <a class="xref" href="runtime-config-client.html#GUC-VACUUM-FREEZE-TABLE-AGE">vacuum_freeze_table_age</a>

  928.       parameter.

  929.      </p></dd><dt id="RELOPTION-AUTOVACUUM-MULTIXACT-FREEZE-MIN-AGE"><span class="term"><code class="literal">autovacuum_multixact_freeze_min_age</code>, <code class="literal">toast.autovacuum_multixact_freeze_min_age</code> (<code class="type">integer</code>)

  930.     <a id="id-1.9.3.85.6.3.4.16.1.4" class="indexterm"></a>

  931.     </span></dt><dd><p>

  932.       Per-table value for <a class="xref" href="runtime-config-client.html#GUC-VACUUM-MULTIXACT-FREEZE-MIN-AGE">vacuum_multixact_freeze_min_age</a>

  933.       parameter.  Note that autovacuum will ignore

  934.       per-table <code class="literal">autovacuum_multixact_freeze_min_age</code> parameters

  935.       that are larger than half the

  936.       system-wide <a class="xref" href="runtime-config-autovacuum.html#GUC-AUTOVACUUM-MULTIXACT-FREEZE-MAX-AGE">autovacuum_multixact_freeze_max_age</a>

  937.       setting.

  938.      </p></dd><dt id="RELOPTION-AUTOVACUUM-MULTIXACT-FREEZE-MAX-AGE"><span class="term"><code class="literal">autovacuum_multixact_freeze_max_age</code>, <code class="literal">toast.autovacuum_multixact_freeze_max_age</code> (<code class="type">integer</code>)

  939.     <a id="id-1.9.3.85.6.3.4.17.1.4" class="indexterm"></a>

  940.     </span></dt><dd><p>

  941.       Per-table value

  942.       for <a class="xref" href="runtime-config-autovacuum.html#GUC-AUTOVACUUM-MULTIXACT-FREEZE-MAX-AGE">autovacuum_multixact_freeze_max_age</a> parameter.

  943.       Note that autovacuum will ignore

  944.       per-table <code class="literal">autovacuum_multixact_freeze_max_age</code> parameters

  945.       that are larger than the system-wide setting (it can only be set

  946.       smaller).

  947.      </p></dd><dt id="RELOPTION-AUTOVACUUM-MULTIXACT-FREEZE-TABLE-AGE"><span class="term"><code class="literal">autovacuum_multixact_freeze_table_age</code>, <code class="literal">toast.autovacuum_multixact_freeze_table_age</code> (<code class="type">integer</code>)

  948.     <a id="id-1.9.3.85.6.3.4.18.1.4" class="indexterm"></a>

  949.     </span></dt><dd><p>

  950.       Per-table value

  951.       for <a class="xref" href="runtime-config-client.html#GUC-VACUUM-MULTIXACT-FREEZE-TABLE-AGE">vacuum_multixact_freeze_table_age</a> parameter.

  952.      </p></dd><dt id="RELOPTION-LOG-AUTOVACUUM-MIN-DURATION"><span class="term"><code class="literal">log_autovacuum_min_duration</code>, <code class="literal">toast.log_autovacuum_min_duration</code> (<code class="type">integer</code>)

  953.     <a id="id-1.9.3.85.6.3.4.19.1.4" class="indexterm"></a>

  954.     </span></dt><dd><p>

  955.       Per-table value for <a class="xref" href="runtime-config-autovacuum.html#GUC-LOG-AUTOVACUUM-MIN-DURATION">log_autovacuum_min_duration</a>

  956.       parameter.

  957.      </p></dd><dt id="RELOPTION-USER-CATALOG-TABLE"><span class="term"><code class="literal">user_catalog_table</code> (<code class="type">boolean</code>)

  958.     <a id="id-1.9.3.85.6.3.4.20.1.3" class="indexterm"></a>

  959.     </span></dt><dd><p>

  960.       Declare the table as an additional catalog table for purposes of

  961.       logical replication. See

  962.       <a class="xref" href="logicaldecoding-output-plugin.html#LOGICALDECODING-CAPABILITIES" title="48.6.2. Capabilities">Section 48.6.2</a> for details.

  963.       This parameter cannot be set for TOAST tables.

  964.      </p></dd></dl></div></div></div><div class="refsect1" id="SQL-CREATETABLE-NOTES"><h2>Notes</h2><p>

  965.      <span class="productname">PostgreSQL</span> automatically creates an

  966.      index for each unique constraint and primary key constraint to

  967.      enforce uniqueness.  Thus, it is not necessary to create an

  968.      index explicitly for primary key columns.  (See <a class="xref" href="sql-createindex.html" title="CREATE INDEX"><span class="refentrytitle">CREATE INDEX</span></a> for more information.)

  969.     </p><p>

  970.      Unique constraints and primary keys are not inherited in the

  971.      current implementation.  This makes the combination of

  972.      inheritance and unique constraints rather dysfunctional.

  973.     </p><p>

  974.      A table cannot have more than 1600 columns.  (In practice, the

  975.      effective limit is usually lower because of tuple-length constraints.)

  976.     </p></div><div class="refsect1" id="SQL-CREATETABLE-EXAMPLES"><h2>Examples</h2><p>

  977.    Create table <code class="structname">films</code> and table

  978.    <code class="structname">distributors</code>:

  979. 

  980. </p><pre class="programlisting">

  981. CREATE TABLE films (

  982.     code        char(5) CONSTRAINT firstkey PRIMARY KEY,

  983.     title       varchar(40) NOT NULL,

  984.     did         integer NOT NULL,

  985.     date_prod   date,

  986.     kind        varchar(10),

  987.     len         interval hour to minute

  988. );

  989. 

  990. CREATE TABLE distributors (

  991.      did    integer PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,

  992.      name   varchar(40) NOT NULL CHECK (name &lt;&gt; '')

  993. );

  994. </pre><p>

  995.   </p><p>

  996.    Create a table with a 2-dimensional array:

  997. 

  998. </p><pre class="programlisting">

  999. CREATE TABLE array_int (

  1000.     vector  int[][]

  1001. );

  1002. </pre><p>

  1003.   </p><p>

  1004.    Define a unique table constraint for the table

  1005.    <code class="literal">films</code>.  Unique table constraints can be defined

  1006.    on one or more columns of the table:

  1007. 

  1008. </p><pre class="programlisting">

  1009. CREATE TABLE films (

  1010.     code        char(5),

  1011.     title       varchar(40),

  1012.     did         integer,

  1013.     date_prod   date,

  1014.     kind        varchar(10),

  1015.     len         interval hour to minute,

  1016.     CONSTRAINT production UNIQUE(date_prod)

  1017. );

  1018. </pre><p>

  1019.   </p><p>

  1020.    Define a check column constraint:

  1021. 

  1022. </p><pre class="programlisting">

  1023. CREATE TABLE distributors (

  1024.     did     integer CHECK (did &gt; 100),

  1025.     name    varchar(40)

  1026. );

  1027. </pre><p>

  1028.   </p><p>

  1029.    Define a check table constraint:

  1030. 

  1031. </p><pre class="programlisting">

  1032. CREATE TABLE distributors (

  1033.     did     integer,

  1034.     name    varchar(40),

  1035.     CONSTRAINT con1 CHECK (did &gt; 100 AND name &lt;&gt; '')

  1036. );

  1037. </pre><p>

  1038.   </p><p>

  1039.    Define a primary key table constraint for the table

  1040.    <code class="structname">films</code>:

  1041. 

  1042. </p><pre class="programlisting">

  1043. CREATE TABLE films (

  1044.     code        char(5),

  1045.     title       varchar(40),

  1046.     did         integer,

  1047.     date_prod   date,

  1048.     kind        varchar(10),

  1049.     len         interval hour to minute,

  1050.     CONSTRAINT code_title PRIMARY KEY(code,title)

  1051. );

  1052. </pre><p>

  1053.   </p><p>

  1054.    Define a primary key constraint for table

  1055.    <code class="structname">distributors</code>.  The following two examples are

  1056.    equivalent, the first using the table constraint syntax, the second

  1057.    the column constraint syntax:

  1058. 

  1059. </p><pre class="programlisting">

  1060. CREATE TABLE distributors (

  1061.     did     integer,

  1062.     name    varchar(40),

  1063.     PRIMARY KEY(did)

  1064. );

  1065. 

  1066. CREATE TABLE distributors (

  1067.     did     integer PRIMARY KEY,

  1068.     name    varchar(40)

  1069. );

  1070. </pre><p>

  1071.   </p><p>

  1072.    Assign a literal constant default value for the column

  1073.    <code class="literal">name</code>, arrange for the default value of column

  1074.    <code class="literal">did</code> to be generated by selecting the next value

  1075.    of a sequence object, and make the default value of

  1076.    <code class="literal">modtime</code> be the time at which the row is

  1077.    inserted:

  1078. 

  1079. </p><pre class="programlisting">

  1080. CREATE TABLE distributors (

  1081.     name      varchar(40) DEFAULT 'Luso Films',

  1082.     did       integer DEFAULT nextval('distributors_serial'),

  1083.     modtime   timestamp DEFAULT current_timestamp

  1084. );

  1085. </pre><p>

  1086.   </p><p>

  1087.    Define two <code class="literal">NOT NULL</code> column constraints on the table

  1088.    <code class="classname">distributors</code>, one of which is explicitly

  1089.    given a name:

  1090. 

  1091. </p><pre class="programlisting">

  1092. CREATE TABLE distributors (

  1093.     did     integer CONSTRAINT no_null NOT NULL,

  1094.     name    varchar(40) NOT NULL

  1095. );

  1096. </pre><p>

  1097.     </p><p>

  1098.      Define a unique constraint for the <code class="literal">name</code> column:

  1099. 

  1100. </p><pre class="programlisting">

  1101. CREATE TABLE distributors (

  1102.     did     integer,

  1103.     name    varchar(40) UNIQUE

  1104. );

  1105. </pre><p>

  1106. 

  1107.      The same, specified as a table constraint:

  1108. 

  1109. </p><pre class="programlisting">

  1110. CREATE TABLE distributors (

  1111.     did     integer,

  1112.     name    varchar(40),

  1113.     UNIQUE(name)

  1114. );

  1115. </pre><p>

  1116.   </p><p>

  1117.    Create the same table, specifying 70% fill factor for both the table

  1118.    and its unique index:

  1119. 

  1120. </p><pre class="programlisting">

  1121. CREATE TABLE distributors (

  1122.     did     integer,

  1123.     name    varchar(40),

  1124.     UNIQUE(name) WITH (fillfactor=70)

  1125. )

  1126. WITH (fillfactor=70);

  1127. </pre><p>

  1128.   </p><p>

  1129.    Create table <code class="structname">circles</code> with an exclusion

  1130.    constraint that prevents any two circles from overlapping:

  1131. 

  1132. </p><pre class="programlisting">

  1133. CREATE TABLE circles (

  1134.     c circle,

  1135.     EXCLUDE USING gist (c WITH &amp;&amp;)

  1136. );

  1137. </pre><p>

  1138.   </p><p>

  1139.    Create table <code class="structname">cinemas</code> in tablespace <code class="structname">diskvol1</code>:

  1140. 

  1141. </p><pre class="programlisting">

  1142. CREATE TABLE cinemas (

  1143.         id serial,

  1144.         name text,

  1145.         location text

  1146. ) TABLESPACE diskvol1;

  1147. </pre><p>

  1148.   </p><p>

  1149.    Create a composite type and a typed table:

  1150. </p><pre class="programlisting">

  1151. CREATE TYPE employee_type AS (name text, salary numeric);

  1152. 

  1153. CREATE TABLE employees OF employee_type (

  1154.     PRIMARY KEY (name),

  1155.     salary WITH OPTIONS DEFAULT 1000

  1156. );

  1157. </pre><p>

  1158.    Create a range partitioned table:

  1159. </p><pre class="programlisting">

  1160. CREATE TABLE measurement (

  1161.     logdate         date not null,

  1162.     peaktemp        int,

  1163.     unitsales       int

  1164. ) PARTITION BY RANGE (logdate);

  1165. </pre><p>

  1166.    Create a range partitioned table with multiple columns in the partition key:

  1167. </p><pre class="programlisting">

  1168. CREATE TABLE measurement_year_month (

  1169.     logdate         date not null,

  1170.     peaktemp        int,

  1171.     unitsales       int

  1172. ) PARTITION BY RANGE (EXTRACT(YEAR FROM logdate), EXTRACT(MONTH FROM logdate));

  1173. </pre><p>

  1174.    Create a list partitioned table:

  1175. </p><pre class="programlisting">

  1176. CREATE TABLE cities (

  1177.     city_id      bigserial not null,

  1178.     name         text not null,

  1179.     population   bigint

  1180. ) PARTITION BY LIST (left(lower(name), 1));

  1181. </pre><p>

  1182.    Create a hash partitioned table:

  1183. </p><pre class="programlisting">

  1184. CREATE TABLE orders (

  1185.     order_id     bigint not null,

  1186.     cust_id      bigint not null,

  1187.     status       text

  1188. ) PARTITION BY HASH (order_id);

  1189. </pre><p>

  1190.    Create partition of a range partitioned table:

  1191. </p><pre class="programlisting">

  1192. CREATE TABLE measurement_y2016m07

  1193.     PARTITION OF measurement (

  1194.     unitsales DEFAULT 0

  1195. ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');

  1196. </pre><p>

  1197.    Create a few partitions of a range partitioned table with multiple

  1198.    columns in the partition key:

  1199. </p><pre class="programlisting">

  1200. CREATE TABLE measurement_ym_older

  1201.     PARTITION OF measurement_year_month

  1202.     FOR VALUES FROM (MINVALUE, MINVALUE) TO (2016, 11);

  1203. 

  1204. CREATE TABLE measurement_ym_y2016m11

  1205.     PARTITION OF measurement_year_month

  1206.     FOR VALUES FROM (2016, 11) TO (2016, 12);

  1207. 

  1208. CREATE TABLE measurement_ym_y2016m12

  1209.     PARTITION OF measurement_year_month

  1210.     FOR VALUES FROM (2016, 12) TO (2017, 01);

  1211. 

  1212. CREATE TABLE measurement_ym_y2017m01

  1213.     PARTITION OF measurement_year_month

  1214.     FOR VALUES FROM (2017, 01) TO (2017, 02);

  1215. </pre><p>

  1216.    Create partition of a list partitioned table:

  1217. </p><pre class="programlisting">

  1218. CREATE TABLE cities_ab

  1219.     PARTITION OF cities (

  1220.     CONSTRAINT city_id_nonzero CHECK (city_id != 0)

  1221. ) FOR VALUES IN ('a', 'b');

  1222. </pre><p>

  1223.    Create partition of a list partitioned table that is itself further

  1224.    partitioned and then add a partition to it:

  1225. </p><pre class="programlisting">

  1226. CREATE TABLE cities_ab

  1227.     PARTITION OF cities (

  1228.     CONSTRAINT city_id_nonzero CHECK (city_id != 0)

  1229. ) FOR VALUES IN ('a', 'b') PARTITION BY RANGE (population);

  1230. 

  1231. CREATE TABLE cities_ab_10000_to_100000

  1232.     PARTITION OF cities_ab FOR VALUES FROM (10000) TO (100000);

  1233. </pre><p>

  1234.    Create partitions of a hash partitioned table:

  1235. </p><pre class="programlisting">

  1236. CREATE TABLE orders_p1 PARTITION OF orders

  1237.     FOR VALUES WITH (MODULUS 4, REMAINDER 0);

  1238. CREATE TABLE orders_p2 PARTITION OF orders

  1239.     FOR VALUES WITH (MODULUS 4, REMAINDER 1);

  1240. CREATE TABLE orders_p3 PARTITION OF orders

  1241.     FOR VALUES WITH (MODULUS 4, REMAINDER 2);

  1242. CREATE TABLE orders_p4 PARTITION OF orders

  1243.     FOR VALUES WITH (MODULUS 4, REMAINDER 3);

  1244. </pre><p>

  1245.    Create a default partition:

  1246. </p><pre class="programlisting">

  1247. CREATE TABLE cities_partdef

  1248.     PARTITION OF cities DEFAULT;

  1249. </pre></div><div class="refsect1" id="SQL-CREATETABLE-COMPATIBILITY"><h2>Compatibility</h2><p>

  1250.    The <code class="command">CREATE TABLE</code> command conforms to the

  1251.    <acronym class="acronym">SQL</acronym> standard, with exceptions listed below.

  1252.   </p><div class="refsect2" id="id-1.9.3.85.9.3"><h3>Temporary Tables</h3><p>

  1253.     Although the syntax of <code class="literal">CREATE TEMPORARY TABLE</code>

  1254.     resembles that of the SQL standard, the effect is not the same.  In the

  1255.     standard,

  1256.     temporary tables are defined just once and automatically exist (starting

  1257.     with empty contents) in every session that needs them.

  1258.     <span class="productname">PostgreSQL</span> instead

  1259.     requires each session to issue its own <code class="literal">CREATE TEMPORARY

  1260.     TABLE</code> command for each temporary table to be used.  This allows

  1261.     different sessions to use the same temporary table name for different

  1262.     purposes, whereas the standard's approach constrains all instances of a

  1263.     given temporary table name to have the same table structure.

  1264.    </p><p>

  1265.     The standard's definition of the behavior of temporary tables is

  1266.     widely ignored.  <span class="productname">PostgreSQL</span>'s behavior

  1267.     on this point is similar to that of several other SQL databases.

  1268.    </p><p>

  1269.     The SQL standard also distinguishes between global and local temporary

  1270.     tables, where a local temporary table has a separate set of contents for

  1271.     each SQL module within each session, though its definition is still shared

  1272.     across sessions.  Since <span class="productname">PostgreSQL</span> does not

  1273.     support SQL modules, this distinction is not relevant in

  1274.     <span class="productname">PostgreSQL</span>.

  1275.    </p><p>

  1276.     For compatibility's sake, <span class="productname">PostgreSQL</span> will

  1277.     accept the <code class="literal">GLOBAL</code> and <code class="literal">LOCAL</code> keywords

  1278.     in a temporary table declaration, but they currently have no effect.

  1279.     Use of these keywords is discouraged, since future versions of

  1280.     <span class="productname">PostgreSQL</span> might adopt a more

  1281.     standard-compliant interpretation of their meaning.

  1282.    </p><p>

  1283.     The <code class="literal">ON COMMIT</code> clause for temporary tables

  1284.     also resembles the SQL standard, but has some differences.

  1285.     If the <code class="literal">ON COMMIT</code> clause is omitted, SQL specifies that the

  1286.     default behavior is <code class="literal">ON COMMIT DELETE ROWS</code>.  However, the

  1287.     default behavior in <span class="productname">PostgreSQL</span> is

  1288.     <code class="literal">ON COMMIT PRESERVE ROWS</code>.  The <code class="literal">ON COMMIT

  1289.     DROP</code> option does not exist in SQL.

  1290.    </p></div><div class="refsect2" id="id-1.9.3.85.9.4"><h3>Non-Deferred Uniqueness Constraints</h3><p>

  1291.     When a <code class="literal">UNIQUE</code> or <code class="literal">PRIMARY KEY</code> constraint is

  1292.     not deferrable, <span class="productname">PostgreSQL</span> checks for

  1293.     uniqueness immediately whenever a row is inserted or modified.

  1294.     The SQL standard says that uniqueness should be enforced only at

  1295.     the end of the statement; this makes a difference when, for example,

  1296.     a single command updates multiple key values.  To obtain

  1297.     standard-compliant behavior, declare the constraint as

  1298.     <code class="literal">DEFERRABLE</code> but not deferred (i.e., <code class="literal">INITIALLY

  1299.     IMMEDIATE</code>).  Be aware that this can be significantly slower than

  1300.     immediate uniqueness checking.

  1301.    </p></div><div class="refsect2" id="id-1.9.3.85.9.5"><h3>Column Check Constraints</h3><p>

  1302.     The SQL standard says that <code class="literal">CHECK</code> column constraints

  1303.     can only refer to the column they apply to; only <code class="literal">CHECK</code>

  1304.     table constraints can refer to multiple columns.

  1305.     <span class="productname">PostgreSQL</span> does not enforce this

  1306.     restriction; it treats column and table check constraints alike.

  1307.    </p></div><div class="refsect2" id="id-1.9.3.85.9.6"><h3><code class="literal">EXCLUDE</code> Constraint</h3><p>

  1308.     The <code class="literal">EXCLUDE</code> constraint type is a

  1309.     <span class="productname">PostgreSQL</span> extension.

  1310.    </p></div><div class="refsect2" id="id-1.9.3.85.9.7"><h3><code class="literal">NULL</code> <span class="quote">“<span class="quote">Constraint</span>”</span></h3><p>

  1311.     The <code class="literal">NULL</code> <span class="quote">“<span class="quote">constraint</span>”</span> (actually a

  1312.     non-constraint) is a <span class="productname">PostgreSQL</span>

  1313.     extension to the SQL standard that is included for compatibility with some

  1314.     other database systems (and for symmetry with the <code class="literal">NOT

  1315.     NULL</code> constraint).  Since it is the default for any

  1316.     column, its presence is simply noise.

  1317.    </p></div><div class="refsect2" id="id-1.9.3.85.9.8"><h3>Constraint Naming</h3><p>

  1318.     The SQL standard says that table and domain constraints must have names

  1319.     that are unique across the schema containing the table or domain.

  1320.     <span class="productname">PostgreSQL</span> is laxer: it only requires

  1321.     constraint names to be unique across the constraints attached to a

  1322.     particular table or domain.  However, this extra freedom does not exist

  1323.     for index-based constraints (<code class="literal">UNIQUE</code>,

  1324.     <code class="literal">PRIMARY KEY</code>, and <code class="literal">EXCLUDE</code>

  1325.     constraints), because the associated index is named the same as the

  1326.     constraint, and index names must be unique across all relations within

  1327.     the same schema.

  1328.    </p><p>

  1329.     Currently, <span class="productname">PostgreSQL</span> does not record names

  1330.     for <code class="literal">NOT NULL</code> constraints at all, so they are not

  1331.     subject to the uniqueness restriction.  This might change in a future

  1332.     release.

  1333.    </p></div><div class="refsect2" id="id-1.9.3.85.9.9"><h3>Inheritance</h3><p>

  1334.     Multiple inheritance via the <code class="literal">INHERITS</code> clause is

  1335.     a <span class="productname">PostgreSQL</span> language extension.

  1336.     SQL:1999 and later define single inheritance using a

  1337.     different syntax and different semantics.  SQL:1999-style

  1338.     inheritance is not yet supported by

  1339.     <span class="productname">PostgreSQL</span>.

  1340.    </p></div><div class="refsect2" id="id-1.9.3.85.9.10"><h3>Zero-Column Tables</h3><p>

  1341.     <span class="productname">PostgreSQL</span> allows a table of no columns

  1342.     to be created (for example, <code class="literal">CREATE TABLE foo();</code>).  This

  1343.     is an extension from the SQL standard, which does not allow zero-column

  1344.     tables.  Zero-column tables are not in themselves very useful, but

  1345.     disallowing them creates odd special cases for <code class="command">ALTER TABLE

  1346.     DROP COLUMN</code>, so it seems cleaner to ignore this spec restriction.

  1347.    </p></div><div class="refsect2" id="id-1.9.3.85.9.11"><h3>Multiple Identity Columns</h3><p>

  1348.     <span class="productname">PostgreSQL</span> allows a table to have more than one

  1349.     identity column.  The standard specifies that a table can have at most one

  1350.     identity column.  This is relaxed mainly to give more flexibility for

  1351.     doing schema changes or migrations.  Note that

  1352.     the <code class="command">INSERT</code> command supports only one override clause

  1353.     that applies to the entire statement, so having multiple identity columns

  1354.     with different behaviors is not well supported.

  1355.    </p></div><div class="refsect2" id="id-1.9.3.85.9.12"><h3>Generated Columns</h3><p>

  1356.     The option <code class="literal">STORED</code> is not standard but is also used by

  1357.     other SQL implementations.  The SQL standard does not specify the storage

  1358.     of generated columns.

  1359.    </p></div><div class="refsect2" id="id-1.9.3.85.9.13"><h3><code class="literal">LIKE</code> Clause</h3><p>

  1360.     While a <code class="literal">LIKE</code> clause exists in the SQL standard, many of the

  1361.     options that <span class="productname">PostgreSQL</span> accepts for it are not

  1362.     in the standard, and some of the standard's options are not implemented

  1363.     by <span class="productname">PostgreSQL</span>.

  1364.    </p></div><div class="refsect2" id="id-1.9.3.85.9.14"><h3><code class="literal">WITH</code> Clause</h3><p>

  1365.     The <code class="literal">WITH</code> clause is a <span class="productname">PostgreSQL</span>

  1366.     extension; storage parameters are not in the standard.

  1367.    </p></div><div class="refsect2" id="id-1.9.3.85.9.15"><h3>Tablespaces</h3><p>

  1368.     The <span class="productname">PostgreSQL</span> concept of tablespaces is not

  1369.     part of the standard.  Hence, the clauses <code class="literal">TABLESPACE</code>

  1370.     and <code class="literal">USING INDEX TABLESPACE</code> are extensions.

  1371.    </p></div><div class="refsect2" id="id-1.9.3.85.9.16"><h3>Typed Tables</h3><p>

  1372.     Typed tables implement a subset of the SQL standard.  According to

  1373.     the standard, a typed table has columns corresponding to the

  1374.     underlying composite type as well as one other column that is

  1375.     the <span class="quote">“<span class="quote">self-referencing column</span>”</span>.

  1376.     <span class="productname">PostgreSQL</span> does not support self-referencing

  1377.     columns explicitly.

  1378.    </p></div><div class="refsect2" id="id-1.9.3.85.9.17"><h3><code class="literal">PARTITION BY</code> Clause</h3><p>

  1379.     The <code class="literal">PARTITION BY</code> clause is a

  1380.     <span class="productname">PostgreSQL</span> extension.

  1381.    </p></div><div class="refsect2" id="id-1.9.3.85.9.18"><h3><code class="literal">PARTITION OF</code> Clause</h3><p>

  1382.     The <code class="literal">PARTITION OF</code> clause is a

  1383.     <span class="productname">PostgreSQL</span> extension.

  1384.    </p></div></div><div class="refsect1" id="id-1.9.3.85.10"><h2>See Also</h2><span class="simplelist"><a class="xref" href="sql-altertable.html" title="ALTER TABLE"><span class="refentrytitle">ALTER TABLE</span></a>, <a class="xref" href="sql-droptable.html" title="DROP TABLE"><span class="refentrytitle">DROP TABLE</span></a>, <a class="xref" href="sql-createtableas.html" title="CREATE TABLE AS"><span class="refentrytitle">CREATE TABLE AS</span></a>, <a class="xref" href="sql-createtablespace.html" title="CREATE TABLESPACE"><span class="refentrytitle">CREATE TABLESPACE</span></a>, <a class="xref" href="sql-createtype.html" title="CREATE TYPE"><span class="refentrytitle">CREATE TYPE</span></a></span></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="sql-createsubscription.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sql-commands.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="sql-createtableas.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">CREATE SUBSCRIPTION </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> CREATE TABLE AS</td></tr></table></div></body></html>
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